One Rep Max Calculator
Put in the weight and reps from any recent working set. You'll get your predicted 1RM from 7 formulas and a full training percentage table in about 10 seconds.
Free · No sign-up · Instant results
- For trained lifters testing with 6 or fewer reps, predicted 1RMs typically land within 2-5% of a real tested max. That margin is small enough to program from confidently.
- Epley (1985) is in almost every gym app on the market. It earned that position.
- Brzycki (1993) is what academic researchers default to because it's NCAA-validated and runs slightly conservative. Underestimating beats overestimating when you're setting training loads.
- Both the NSCA and NASM tell coaches to use submaximal testing instead of actual max attempts with general fitness clients.
- Keep rep counts under 10 for a useful estimate. Go higher and endurance starts corrupting the number. The formulas weren't designed for 15-rep sets.
What a One Rep Max Actually Is
Your one rep max (1RM), or one repetition maximum, is the heaviest weight you can lift for a single clean rep of a given exercise with good form. In powerlifting, competitions are decided by this number alone. In training, it's the denominator for everything: when a program tells you to lift at 80%, it means 80% of this.
You don't need to attempt your true max to get the number. Load up something you can lift for a few hard reps, enter the weight and reps here, and you'll get an estimate within a few percent of what your actual max would be. For trained lifters using 6 or fewer reps, that estimate is usually accurate enough to build a full program from.
What's the difference between a tested 1RM and a predicted 1RM?
A tested 1RM is what you actually lifted for one successful rep in a max attempt. A predicted 1RM is what a formula calculates from a submaximal set you've already done, like 225 lbs for 5 reps. This calculator gives you the predicted version. It's close to your real max, safer to get, and doesn't require you to go to failure under a heavy bar every time you want updated training numbers.
Training Max vs. Competition Max: Not the Same Number
A training max is a conservatively set working ceiling, usually 85-90% of your true 1RM, that you use as the base for all your weekly load calculations. You're not trying to hit it. You're calculating off it. The intentional gap between training max and true max is what keeps the program from grinding you into the floor every third week.
Jim Wendler's 5/3/1 program is the clearest real-world example. Say your deadlift 1RM is 400 lbs. Your training max is 360 (90%). When the program calls for 85%, you lift 306 lbs, not 340. That 34-lb difference is the whole point. People who plug their true 1RM in as the training max wonder why they stall out by week 8.
Your Predicted 1RM Results
Formula-by-Formula Breakdown
| Formula | Predicted 1RM | Notes |
|---|
Training Percentage Breakdown
Use these load prescriptions in your percentage-based program. Calculated from your consensus predicted 1RM.
| % of 1RM | Working Weight (lbs) | Recommended Use |
|---|
What Is a Good 1RM? Strength Standards by Body Weight
These come from raw powerlifting data, no supportive gear, pulled from thousands of tested lifters across bodyweight classes. Use them as reference points, not judgment. They show you the field, not where you're required to be.
Bodyweight ratios are how you make fair comparisons. A 250-lb bench press means something very different on a 140-lb lifter than on a 250-lb one. For male lifters who've been training consistently for 1-2 years: bodyweight bench, 1.5x bodyweight squat, 2x bodyweight deadlift. Those aren't elite. They're solid intermediate numbers that most dedicated lifters reach.
All values in lbs. Standards represent raw, un-equipped lifting. Dedicated strength standards for bench press and individual lifts available in our in-depth guides.
How One Rep Max Formulas Actually Work
These 7 formulas were built by different researchers between 1985 and 1994, each tested on a different group of athletes. That's why they give slightly different outputs: they're encoding different assumptions about how the relationship between reps, weight, and maximal strength actually behaves.
No single formula has been shown to consistently outperform all the others. Each was validated on a specific population. When you're using yours for programming, the smart call is to average them all, which is what the Consensus 1RM does. It accounts for the cases where one formula happens to be a bad fit for your training background or testing conditions.
Methodology Why This Calculator Shows a Consensus Average
All 7 formulas run simultaneously. Their arithmetic mean becomes the Consensus 1RM. When researchers compare single-formula predictions against a true tested 1RM across diverse athlete populations, averaging multiple formulas consistently reduces error more than picking any one formula and sticking with it.
The 7 included: Epley (1985), Brzycki (1993), Lombardi (1989), Mayhew et al. (1992), O'Conner et al. (1989), Wathen (1994), Lander (1985). For 1-6 rep sets done close to failure, the consensus typically lands within 3% of a tested max for trained lifters. Use a set where you had about 1 rep left in the tank for the most accurate result.
The formula you've seen everywhere. Boyd Epley was the head strength coach at Nebraska for 35 years and founded the NSCA in 1978. He built this for his football athletes and it ended up in almost every piece of commercial fitness software ever made. Solid for 1-10 reps. Gets a bit optimistic above that.
Brzycki is what you'll see cited in most peer-reviewed sports science papers. The NCAA validated it, researchers rely on it, and it tends to run slightly conservative. That conservatism is actually a feature: it's better to slightly underestimate your max than to program off an inflated number, especially for newer lifters.
Lombardi's exponential model is the one you want when you're testing with higher rep sets, 10-15 reps. Epley and Brzycki both lose accuracy up there because endurance starts mattering more than pure strength. Lombardi accounts for that better. If you did a set of 12 to failure, Lombardi's estimate is likely your most reliable one.
Mayhew's team cross-validated this on both trained and untrained populations, which makes it one of the more broadly applicable formulas here. Most other formulas were built on athletes. Mayhew's works reasonably well regardless of training history, so it's worth having in the mix for clients who are newer to lifting.
O'Conner's is the most conservative of the seven. It intentionally undershoots, especially at higher rep counts. For someone brand new to lifting who's about to build their first percentage-based program, that's the right property. You want to start lighter than you think you need to. This formula helps enforce that.
Published in the NSCA's journal and built specifically around power athletes: sprinters, throwers, and Olympic-style weightlifters. If that's your population, Wathen tends to outperform the others. Boyd Epley founded the NSCA in 1978, and Wathen's formula became one of the organization's go-to assessment tools for high-performance sport contexts.
Lander's formula is structurally similar to Brzycki but consistently gives slightly higher estimates. Competitive powerlifters tend to prefer it because a bit of optimism in your predicted max means slightly heavier programming, which can push adaptation. It's not for everyone, but for experienced lifters who know their own tendencies, it works.
| Formula | Best Rep Range | Population | Bias | Endorsed By |
|---|---|---|---|---|
| Epley | 1–10 reps | General | Slight overestimate at high reps | Widely used in fitness software |
| Brzycki | 1–8 reps | General / Research | Conservative | NCAA |
| Lombardi | 10–15 reps | General | Moderate | — |
| Mayhew | 1–10 reps | Trained & Untrained | Moderate | Research literature |
| O'Conner | 1–10 reps | Beginners | Conservative | — |
| Wathen | 1–10 reps | Power Athletes | Moderate | NSCA |
| Lander | 1–8 reps | Powerlifters | Slightly optimistic | — |
One thing to keep in mind: all 7 formulas assume you were close to your actual limit on the set you just did, 0-1 reps left in the tank at RPE 9-10. If you could have done 5 more reps comfortably, the estimate won't be reliable. And above 10 reps, endurance starts doing too much of the work. The formulas weren't designed for 15-rep burnout sets.
If you're not sure: use the consensus average. It's what this calculator defaults to and it's the most defensible choice when you don't know how your body responds to each model. If you're a competitive powerlifter, Wathen tends to predict most accurately for power-focused athletes. Researchers and coaches running institutional testing typically default to Brzycki because it's NCAA-validated and conservative. Testing at 10+ reps? Lombardi is the least wrong in that range. But in day-to-day programming, the consensus is the number you want.
How Athletes and Coaches Use 1RM Numbers in Practice
Powerlifters & Strength Athletes
Powerlifting is scored on single-rep maxes for squat, bench, and deadlift. The 1RM is literally the entire sport. Between meets, coaches use predicted 1RMs to set training loads through a peaking block, usually working from 60% up toward 95% over a 12-16 week cycle as the competition approaches.
Jim Wendler's 5/3/1 is probably the most-used percentage-based strength program in gyms right now. Wendler competed in the 275-lb class with a 2,375-lb total before retiring from competition. His program is entirely built around knowing your numbers and incrementing them slowly. Sheiko's high-volume Russian system works the same way. So does Mike Tuchscherer's RTS methodology. All of them need an accurate input to produce accurate outputs.
Bodybuilders & Physique Athletes
For hypertrophy, the sweet spot is roughly 65-80% of your 1RM, putting you in the 6-15 rep range depending on the movement. Knowing your max means you can load every set with intention instead of adding plates by feel each session and hoping it's close.
Renaissance Periodization (RP Strength), co-founded by Dr. Mike Israetel (PhD in Sport Physiology, ETSU) and Nick Shaw in 2012, is built entirely on this. Their templates prescribe training volume and load in percentages across a mesocycle, and all of it traces back to your 1RM. The RP app, which now serves more than 250,000 clients worldwide, automates those calculations — but it still needs your number as the starting input.
Personal Trainers & Coaches
Most trainers don't ask untrained clients to attempt a true 1RM. The injury risk isn't worth it, and a lot of people don't have the technique to stay safe under a genuine max effort. Instead: pick a weight the client can lift for 5 reps hard, test it, run it through the calculator. Both the NSCA and NASM recommend this submaximal approach for general populations.
From there, the coach can design percentage-based programming, track actual strength development over weeks and months, and make objective decisions about when to increase load. Without an anchor number, "progressively overload" is just an instruction with no mechanism. The NSCA guidelines have the full warm-up and testing protocol if you want specifics.
What You Actually Need for Heavy Training
Three things make a real difference once you're training at serious percentages. None of it is complicated.
A Lifting Belt
A belt increases intra-abdominal pressure on heavy squats and deadlifts. That pressure helps you stay tight and transfer force more efficiently, which means more of your actual strength shows up in the lift. For competitive powerlifters: IPF-approved 10mm lever belt. For everyone else: a 4-inch nylon belt does the same job for about a third of the price and lasts for years. Buy one once, never think about it again.
Shop Lifting Belts on Amazon →Chalk
Grip fails before pulling strength does on heavy deadlifts. That's the experience of most lifters. Magnesium carbonate chalk dries your palms and improves contact with the bar. Bring your own small block. Gym chalk runs out, gets wet, disappears. The blocks are cheap, they last a while, and the difference on a deadlift set you're trying to hold for 5 reps is immediate and obvious.
Shop Gym Chalk on Amazon →A Program That Uses Your 1RM
A predicted max is only useful if you have a program that knows what to do with it. Wendler's 5/3/1 is where most intermediate lifters should start: 90% of your tested 1RM becomes the training max, weekly sets run at 65%, 75%, and 85% of that training max, and you add small increments each cycle. It works because it's conservative enough to let you keep going for years, not because it's clever. For hypertrophy with more structure, RP Strength templates by Israetel and Shaw set volume targets as percentages across a full mesocycle.
Get 5/3/1 Forever on Amazon →Questions About 1RM Calculators
The ones people actually ask.
What is a one rep max (1RM)?
The heaviest weight you can lift for one rep with good form. In powerlifting, competitions are scored on this number alone. In training, it's the number every percentage gets calculated from. When a program says "4 sets at 75%," that 75% is a percentage of your 1RM. Without this number, percentage-based training is just math on a bad foundation.
How accurate is a 1RM calculator?
For trained lifters testing with 6 or fewer reps at close to their actual limit, predicted 1RMs typically land within 2-5% of a real tested max. That's accurate enough to set training weights from. Accuracy drops fast once you go above 10 reps, because at that point endurance is contributing as much as maximal strength, and the formulas weren't built to account for that. This calculator averages 7 formulas to reduce the error from any single one being a poor fit for how you train.
Which 1RM formula is the most accurate?
It depends on who you are and how you tested. Epley is the most widely used and holds up well across most situations. Brzycki is what researchers default to for its consistency and NCAA validation. Wathen tends to predict best for power athletes. No single formula wins every time across every population and rep range, so the consensus average is the most practical answer for general use. If you're an intermediate lifter with no strong reason to prefer one formula, average them all and move on.
How many reps should I use for the most accurate estimate?
3-6 reps, with about 1 rep left in the tank when you stop. The closer to failure you are, the tighter the estimate. A true 3-rep max gives you a better number than a 3-rep set where you could have done 5 more. If you could have kept going easily, the input isn't reliable and the output won't be either.
What's the difference between a training max and a competition max?
A training max is 85-90% of your true tested 1RM. It's the number you calculate your weekly percentages from, not a number you're trying to lift. The gap is intentional: training off your actual ceiling every week grinds you down fast.
Wendler's 5/3/1 is the best illustration of this. Your bench 1RM is 300 lbs. Training max is 270 (90%). The heaviest set in the program's third week, 85% of training max, is 230 lbs, not 255. That 25-lb difference is what makes the program sustainable for years instead of weeks. Most people who stall on 5/3/1 skipped this step and built their training around their actual max instead of 90% of it.
Is it safe to test my actual 1RM?
Riskier than a submaximal test, yes. The NSCA and NASM both recommend against actual max testing for general fitness clients for good reason. If you're experienced and want to test a true max anyway: warm up methodically with small weight jumps, use a spotter or safety equipment, and limit yourself to 2-3 heavy singles. Don't go into a max attempt cold. See our guide: How to Test Your 1RM Safely.
What's a good 1RM for bench press, squat, or deadlift?
It depends entirely on your bodyweight, sex, age, and training history. The Strength Standards table on this page has the full breakdown. Quick reference for male lifters at an intermediate level: bodyweight bench, 1.5x bodyweight squat, 2x bodyweight deadlift. For women at the same level: 0.65x bodyweight bench, 1x bodyweight squat, 1.25x bodyweight deadlift. Most people hit these numbers after 1-2 years of consistent structured training. See our Bench Press Standards page for weight-class specific breakdowns.
Can I use a 1RM calculator for any exercise?
Yes. The formulas are exercise-agnostic: bench press, squat, deadlift, overhead press, barbell row, Romanian deadlift, weighted pull-up, all of it. What determines accuracy isn't the movement, it's how close to your limit you were on the set you tested with. We also have dedicated calculators for bench press, squat, and deadlift with lift-specific context if you want those.
How do I use my 1RM for percentage-based programming?
Multiply your 1RM by the percentage your program calls for. If 5/3/1 says "85% this week" and you're working off a 270-lb training max, you're lifting 230 lbs. The training percentage table that appears after you calculate shows exact weights at every 5% increment from 50-100% of your predicted 1RM.
For context: 65-80% of 1RM is the hypertrophy range for most people. 80-95% is where strength work lives. Our Training Percentages Guide maps these onto specific programs including 5/3/1, GZCLP, nSuns, and Texas Method.
How often should I recalculate?
Every 4-8 weeks, or at the end of each training block. Your strength builds over time, and training off an old 1RM means your percentages are lighter than they should be. You'll be underloading without realizing it. 5/3/1 builds this in by adding 5 lbs to upper body training maxes and 10 lbs to lower body training maxes after each cycle. It takes one submaximal test set and about a minute to update your numbers. Do it.